Propeller arrangement



Feb. 28,1933.. M DREXL 1,899,434

PROPELLER ARRANGEMENT Filed July 15, 1931 ,T11/venten f hicle for taking this impetus, the receiver 8 v f consisting of a ring with a very flat projection or of slightly conical rollers arranged in a circle. The pressure ringband thrust bearing arev no longer necessary, and" the shiftable bearing 1l now serves for adjusting' the rotary bladesV (Figs. VI-YIII) for v forward and reverse impulse.

blades'cann'ot actually screw forward: in `a helical line immediately after they are .start.l

ed up, but are'compelledto rotate ina-,circle vehicle. They therefore produce right from the outset ofthe rotation ayrearwardlydiei rected How of the medium, which is desirable for a fan but is verydetrimentalfor afpro' peller, as this obtains nosolidsupport on the; rearwardly escaping medium'land thus .ef-" fects no strong thrust andl-canjjovercome no vstrong resista-noel` Moreoverthis unnec-A essary and detrimental flinging bacli'of the medium remains more or'less', even#duringl effective propellingof thefvehicle,a'sltliis can never followxthe `propeller"with. the .axialspeed corresponding. toits Ascrew operationi- InV the new arrangement hoiv'everigias caribe seen from the'diagram illustrated in Fig.A IV,

. the working,V surface 3 r'screws itself slightly forwardV in the'direction of travelimmediat the cam-'surface 7;

ly after it isset inA operation, leavinr thefvehicle` behind, Vthat is without contacting 'with its'thrustrreceiver 8,-andtravels in vits "helical line yCorrespending` -to jits `=pitch, out of" the position Afinto.theposition-"B asit' does `not f as yet need tof drive the vehicle,'t`hat is, its` camjsurface 75 j doesnotconta'ct with the thrust and is first compelled byf vthis (or more correctly by the traveling resistance of the ve;- hiclerigidly connected to the receiver) to *56 pass slightly'forward )out of' its freehelical slightly forwardlyk .f'directed zino'v'ement (shownat top of illustration) is to the axially slightly rearwardly 1 displaced position (shown at bottornofillustration).`The blades at 'the contact `point are of double wedge-shaped' cross section, withthe taperof the working surface 8"longer than that-off `During this short travel, the actual worl? ingoperation, theworking surface 8v presses *and suddenly the mediunn which has" remained substantially constant upto this min'- ute, Vout of its posit-ion ofrest-'andforces itK very vquickly axially towards the rear,` there'- by exerting a vflatfblow with itsentirelwide side. (shown` 'in the" bottom of drawing).`

As however air and water, as is known, offer at first but not for long an extremely great resistance to the rapid displacement out of the osition of rest, which resistance is a hundred times greater than in the eddy of the known propeller, the thrust Vreceiver 8 will ushedV strongly forward if the blade stri es sufficiently rapidly and not too far towards the Vrear and the resistance is not too great, that it does not exceed about 200 i A kilograms er Hl). This forward movement In the known propeller arrangement the is fdue` to t e strong initial resistance of the medium against its sudden displacement towards the rear, so that the vehicle is strongi vly'pushedforward in itsdirection of travel. until they have gained sufficient" speed and" develop thrust force toV effectivelyrpropel,the

" Asisoon as the mediumis pressed so strongtowards the rear or the vehicle is pushed C, the medium, 'owing' to the speed and short Qduration-with\whichv it islbeaten by the en'- ti're wide' side'of thelblade, has not time to properlycomeout of itsposition' of rest and to vescape towards the rear. 1 Consequently tcanA n'o longer form land continuallysup#v plement a rearwardly directed strong current which would hinder to a maximum' extent" thel further strong. grippingv of the blades. The'air on -thepressure'side of the yblade is'slig'htly compressed (seebottoin of illustration) andworlring vsurface 3 is forced towards the rear the air being slightly rarefied onQthe suction side so that `the working surface suckedtowards therear, but in real# Vity'only a fraction of a millimetro and only is insufficient for during a' short time which the' complete starting up.V `Then in the next moment the blade duringits long path from Cy to -D the workingsurface screws forward agamalone, withoutthef vehicle,` land cuts the mediumfexactlyin 'its helical line as far as itf is not-prevented by lthe massVV proper from `being axially accelerated'toa minimum relative `to1V the -vehicle',`that is without disn placement morev towards the' rear thanA tewar'ds the front, so `that with Y very slight Weight -it'only produces veryslight flowing V.and during-the next sudden attacking of the imedium`v can form a supporting point almost exactly as strong as the first time, and the rotary frceof'the engine is always almost completely Vconverted into. effective impulsion ofytheuvehicle YMoreover owing to this lowkheing lacking, the blades: according' to thenew arrangement, can rotate much more quickly.ipjthan` heretoforewithou't losing in efiiciency; Consequently'the' new propeller may alsof-be enclosed in a narrow space, have a much ls'irgern'umloerv of blades anda much en@ f smaller diameteiny v land *het `rd'rigven.." directly from Vthev high: speed" engine rwithoutfreduc tiongefr. f Vf Y The7 manner of -cperation vin the construction according to VITVIII is in ip rinci ple the saine.;y Iii-'this instance, according lto i the Vdiagrain shown {inf-Fig. 5V, ythe:lworking:jvr

surface?, 'ofthe bladesuspended onthe trans verse jaxle 6' and pushed 'ong inl front Vof saine when travelling -5on,"is pushed by the medium"` i out ofthe inoperative positionA, beeause it does'not requireto pushgon the vehicle, andcoines into the position B,-"W'ithits frontedge somewhat axially in advance A(seeupperpor-v tion .0f illustration) Inthis position -itco n`- tactsfwith` the rollery 10,'which does notfarrestv it iin its, rotation,-. but forces it to suddenly'V yieldislig-htly` axiallyin thei opposite direc-f j tionto that oftravel, and to-suddenly eeet.

a *rapidandsho'rt; flat yblow` against :the stagf nant mediumuntil, owingfto the :greatr'esistrf 30, toits- :free4 forward screwing fintoffthe `posify ance of `'saine Vagai'nstgrapid ,displacement-,f has wed-ged the` rollerand with same-the im' the .positionV C, where, the working period is LThe vehicle movesv .easier iandfurther ffor ward s under the "iii'diyidual impulses `Yand, ref tains the acceleration xr'eceived'- `for alonger.l period the less fthejtravellingresistance is, so

Y that the vehicleddes notrec'eive. excessive lim-g` into `contact at differentutimes and during that theinaXim-um speed of travel co rrespond ing vto @the actually-` ;fexisting'conditions? ofd power and iresistance, is j automatically i obtained :without agch'angegear,vsuch as is. 'nee-1 l Y -LIII-Y'If and VIIIand setforthn claims 2 f ,to More()very the blades maygbewmadeof f lighter weight, with` a rnuclilmorefavorablel essary in -the ,lniownv Inotorcars Injorder pulses from` the y@entire propeller' and must continue 'to travel for a' longer period.. exclusively4 by its inertia mo'rnent, therv nlln'ilo'ery pairs of blades l' (herefour) andfthat ofthe r contacts 9,V 10 areselected 'so' thatithy come,

the Lworking -pausegof onef'pair of y:blades -`the v*strong impulsesof the `remaining rpairs occur successively and thus effect-,'alpracticallygune;

interrupted .and vibratiomfree strong,t l1iust.

In order ,toallovv .theveh'icle torunback wards, the vdriving shaft2` `is',:accordin'glto Figsfziiil and vnnimerieiy snowedto 'circus late in the opposite-1 direction',` f :The lila-des`V then press withl their rearwardly directed' cam surfaces 7 onto forwardlyl directed prof "jections `9 of the.pressure'receiver Sf'in an analogousr manner tothatwabove rdescri-bed and illustratedr in- Fig; for the vfor-ward repulsion. In theiarrangem'ent; according-:to Y

Figs. VI-VII- forsV, the reversingl gear? bear-,

i ing 11 land .therefore alsojthe transv arse-` axle fis'merely pushedlslightly towardsthe viront .(topl of illustrfation);.-f` :Gonsequentlyf the l workin vsurfsalces are situated-f` with j Ytheir fronte gefdirected towards the'rear and-ex-l ert thev abovevdescribed'operationfas 'a strong rearward pull, vas showndiagramrnatically;in` p, the second portion effig;V,f"where,the blade screws `freely' forward outy of thepositi0n A f into the position Bfgand, betweenitsipositionsi 'Brand Cf, is" forced vforvvards;by thelrolle'rs flO andthus exertsthe thrustgjtowards they! rear indicatedby the'vertical'arrow;

` of 'thepr-opeller, 'in the foi-Invof. a mass? accelfr eration, and'in the intermittent imparting of 'An'v` invention 'apparently'r similar, of lthe same inventor, is known, but has not Aattained its aim, because ininverse ina-mier, instead of yz ypreventing the slippirigl it `is based kon'A the this.4 stored force',k to the svehicle, whereas in i realityfitIis'eXa-ctlylthelopposite to that which rishere`tli'e. case, the workingfsupportingfs'ur- L face-during its axial a oscillations Gmu'stbe i j l free f -froni'gzall unnecessaryzfmasszand consetquently thezoperationis also-not destroyed by theelasticity;cthelfaiiialgforcingback-of'the vblades i against the medium; and/also, the iin-1 ,f parting, of the lilade" jthrustj toV the vehicle rnust not'occurthrough "thepropeller `axle lor. even "througharringQarrangedon-a rldisc 1 mountedfon lthe axle, butgonlyxbydirect contact hetweensthe 'vehicle' body and lthe:` thrust? xcentre gofflthej "blade surfaces, as Vhere gat;

striking; back and the rapid screwing'fforward meansfare here a employedl 'assshownI in shape,y as regardsftov eiciencyand safetyk i ,againstjfracturd thanpin thel known systemf` as they; arefactuaglly supported fat their v.most 5 delicate points; slightly outof theirl centre-by thrusitfforcen j' Further; in order -ftdprevent ythe ,good eili-py cien'cyr i .from n suffering ythrough l''the sli ding 1 friction, on inclined pressure surfaces', rollers Y 101 are employed in practiceiinstead'of-fthe,.

pressure surfacesi9f on the impulse receiver 8,5

shown forf'thesake'ofclearness.; Ifclaimag-L; i

ing-iii yconloinaftio`n-a drivingshaft, blades :the thrust; mceiveras. soonas theyfdevelop l v f flee y:A propeller arrangement fory propelled y vehicles with sliortstriking blade's,comprjg- I y A mountedgonfand adapted toirotate-iwith said I i shaft 'axiallyshiftable during thework, actualv T135 f `f working;surfaces"v `of ysaid blades1ra-rranged'ji with axialfplayreans for"caus`i'ng axial push-v E s ing `haclrof leach-@of :said` Working siirfaces Y individually (at fitsfcentre of for e-ectingij ajflat bloweiand impar-ting'fai rproflso y pel-ler thrustuproduced.a thrust imparting* element foreach ofsaid blades, and a thrustV receiving element for each of saidlblades, said means becomingI operative between said.-y thrust imparting element and said thrust rel ceiving element. j

2.v An arrangement as specifiediin claim 1-, comprising in combination with the blades` Vand the axially fix'ed'drivingV shaft,`a thin plate resilientinaxial direction Vand rigid in turning direction" connectingsaid `blades adapted to allow the freelaxial screwing forv ward and striking back ofsaid pendently of saidshaftn n i i 3..'An arrangement as specified in claiml,

blades findecomprising` in Vcombination?withl the blades;

and the axiallynonj-shiftable difivingshaft, an arm rigidly mounted -vertically on said` shaft'V adapted to allow the freeaxialiplay of`` said blades on .said .shaft and to pull Vsaid blades towards Vtlieirfront edges andto-pusif tasting cheeks at an inclinejto the axis; adaptedtojmove said bladestowards their `rea-r edges during its rotation.A f 4, An arrangementas'speciiied in claimf 1,-` comprising .in combinationwithr the l blades and the driving shaft, a liub carrying said blades Vloosely andA shiftablymounted 'on fsaid shaft, catch larmsfrigidly connected-to said shaft adapted to. impart therotary power to said blades, contacting ch'eeksvon` sai-d catch arms; inclinedrtojithe'axis ofsaidvsliarft,` and contactingcheeks on said blades alsoV extend-V ing fatV aninclinejto the axisadapted tomove slightlyaway from the contacting cheeks on said catcharins during the axialshiftingiback of said blades to allow'. the free axial'playof said blades.- f-f: jf

5. An arrangement as 'specified'` in claim "l, comprisingf'in combination-with the blades -and theV drivingshaft, a-hubA4 carrying said blades, loosely and fshiftably mounted onsaid y shaft,- catchi'arms vrigidly `connected' tofsaidf shaft adapted 'to impart the rotary power to said blades, contacting cheeks on-said catch arms, Vinclined to theVV axis V4o'f said shaft, contacting' cheeksV on said -bla'desalso :extending at an `incline to the axisv adapted to move slightly away from the contacting cheeks'on said icatch arnis during the axial shifting back of said blades, and guiderollers between said cheeks. adapted-tol allowth'e free axial` play of said blades.l .1

6. An" arrangement as specified in claiin 1,

comprising in combination with the blades and the driving shaft', a hub carryingsaid blades, looselyand shiftably mounted on 4said shaft, e catchV arms rigidly Y connected to said shaft adapted to impart the rotary'power to said blades, contacting 'cheeks onsaid catch arms inclined Vto the axis of said shaft, conon said blades also Vextending slightly away-from the contacting cheeksfon said catcharms during: the axial shifting back of,V said blades, and an elongated ele! ment slightl axially bendable backwards and forwards a apted `to shift apart said cheeks to allow the free axial pla-y of said blades.

-7,' An arrangementas specified in claim 1, comprising in combination with the axially non-shi'ftable. driving shaft and the blades,

`elementsjadapted torotate said blades to enable'thefree play ofsaid blades independent-k -ly ofsaid `shalft,said' elements causing an out- Viow at their edge-opposite to the desired d1- 9. An arrangement as specified inv claim 1, (comprising-in combinationwith the blades,

small `inclined"projections inthe pressure centrej of said blades adapted; to effect the alternating short'freeingof said blades from the'thrustof the vehicle andthestill shorter Areloading of same` and to lcause a strong for- .warddrive. of the vehicle, athrust receiver,

and rollers onsaid thrust receiver" adapted to come .into contact with said projections during the freeforward screwing of said blades.

lO. Anarrangenient as speciedin claim l, comprising liii combination with the blades, smallinclinedcams in the pressure centre of saidblades adapted to edect tliealternating short freeing of said blades from the thrustV ofuthevehicle and the still shorter reloading of same and `to causeja strong forward drive of the vehicle', a thrustreceiver, androllers on said thrust Vreceiver adapted to come into con- `tact-with said cams during the free forward screwing of said blades. s

11.l An arrangement as specified in claim 1, comprising in .combination with the blades, small. inclined projections in the pressure centre of said' blades adapted to effect the alternating short freeing of said blades from the thrustof thevehicle and the still shorter i reloading of same and to cause` a strong forward-drive of the vehicle, and rollers on the `vehicleframe adapte-'dto come into contact with* said `projections Vduring the free forward screwing of said blades.

v `12i`An arrangement Las specified'in'claim 1,

in 'which the rapid pressingback vof the freely screwingV forwardblades on encountering the thrust. receiving element is .effected by a pressure liquid' between the thrust imparting element and the thrust receiving element.

13. .An arrangement'as specified in'clairn 1, in which the rapidpressing back of the freely screwing forward yblades on encountering the thrust receiving element is edected by the reaction vofa body betweenthe thrust imparting element andthe thrust receiving element.

l 14. An arrangement as specified inclaim 1,

vcomprising in combination With :the l bladeS adapted to Swing axially' yindependently the `ones to the others and, the thrust receiving n element, a'pluralty of'cams-onqsadblades, n en e 5 a plurality of Vprojectonsonfsaid thrust re.- ce'vng element adapted t0 .produce annn- Q ylerrluptel and Vbratonless thrust on the ve-y f :In testimony whereof `IfaHx mysignature. 1

-10 MART11\ILDREXL;y 

